Advanced Merkel Cell Carcinoma: A New Case of Spontaneous Regression

Abstract

Merkel cell carcinoma is an aggressive skin neoplasm affecting predominantly older or immunosuppressed patients. The progression to metastatic disease is frequent while spontaneous regression is quite uncommon. Chronic sun exposure and infection by Merkel cell polyomavirus are known etiopathogenic factors. An 89-year-old female was observed with a locally advanced Merkel cell carcinoma of the left nasal ala. Lymph node metastases in left submandibular region were clinically apparent and confirmed by fine-needle aspiration. A solitary metastasis in the liver was identified by positron-emission tomography/computed tomography with (68)Ga-DOTATOC. While she was waiting for palliative radiation therapy, the patient experienced a complete clinical remission of the primary tumor and regional lymph nodes metastases occurring after 6 weeks. A liver ultrasonography disclosed remission of the liver metastasis as well. The spontaneous remission is rarely reported in medical literature. As far as we know, this is the first report in Portugal. The underlying mechanism of the spontaneous remission remains unknown, although theoretically it can be explained by the development of an efficient immune response against the tumor.